A new study suggests that human beings have a sixth taste. Along with sweet, salty, sour, bitter and umami, "starchy" is now recognized as an official taste.
In a study led by Juyun Lim, Associate Professor of Food Science & Technology at Oregon State University, researchers found that the human taste bud can detect carbohydrates found in starchy foods such as pizza, pasta, and potatoes.
To test the sixth-taste theory, Dr. Lim and her team conducted an experiment with a sample of 22 volunteers. She took several complex carbohydrates, dissolved them into varying degrees of liquid solutions and had the participants consume and rate on the taste.
Previous studies suggested that human beings were only capable of recognizing the taste of sugar in carbohydrates because the saliva excretes enzymes that work to break down starch molecules and transform them into simple sugars. Before the procedure, Dr. Lim gave the participants a compound to block their sweet receptors.
So even if the sweet receptors of these participants were blocked, they were still able to taste the starch. This led Dr. Lim and her team to conclude that human being can recognize the taste of starch before they are broken down into sugar.
Dr. Lim told the New Scientist that the ability to taste starchy flavors is useful to humans. Since starch makes a valuable source for slow-releasing energy, detecting food with high starch content is important.
The findings could also explain why most people prefer and crave for more complex carbs. Dr. Lim explained that "Sugar tastes great in the short term, but if you're offered chocolate and bread, you might eat a small amount of the chocolate, but you'd choose the bread in larger amounts or as a daily staple."
Despite the preliminary findings, starch lacks the requirement to be considered a primary taste because there is still need to identify specific starch receptors in the tongue.